The present invention relates to a transparent liquid food, and more particularly, to a transparent liquid food including transparent beverages such as teas beverages which are extracts from tea leaves or other plants, straight coffee or the like; clear soups or brothes such as consomme soup, brothes of boiled beans, Japanese hotchpotch, water-boiled vegetables, daily dish, Japanese chowder or pickles, or the like; seasoning materials such as noodle soup or sauce; or the like.
It is widely known that sucrose fatty acid ester (hereinafter referred to as merely "SE") is added to the canned or packed low-acidic beverages containing milk components or precipitable components, such as coffee with milk, tea with milk, cocoa, potage soup, azuki-bean soup or the like, so as to prevent the spoilage thereof by thermoduric endospores (see "Nippon Shokuhin Kogyo Gakkaishi", 35(10), pp. 706-708 (1988) by Nobuyuki SUWA; and "The Canners Journal", 68(1), pp. 86-90 (1989) by Mitsuyuki TANAKA). Especially, it is known that the SE containing not less than 70% by weight of palmitic acid and not more than 30% by weight of stearic acid based on the weight of constitutive fatty acids thereof, and having a monoester content of 70 to 90% by weight (see Japanese Patent Application Laid-open (Kokai) No. 56-18578(1981) and Japanese Patent Application Laid-open (Kokai) No. 60-199345(1985)) are used for preventing the spoilage of foods.
As commercially available conventional SE used for preventing the spoilage of foods or the like, there have been exemplified an SE containing palmitic acid of about 80% by weight based on the weight of constitutive fatty acids thereof and having a monoester content of about 70% by weight ("Ryoto Sugar Ester P-1570" produced by Mitsubishi-Kagaku Foods Corporation), an SE containing palmitic acid of about 80% by weight based on the weight of constitutive fatty acids thereof and having a monoester content of about 80% by weight ("Ryoto Sugar Ester P-1670" produced by Mitsubishi-Kagaku Foods Corporation), or the like.
On the other hand, low-acidic teas beverages such as straight tea, Japanese tea, oolong tea or the like are unlikely to be spoiled by the endospores, because these teas beverages are low-nutritive as compared to the afore-mentioned canned or packed low-acidic beverages containing milk components or precipitable components, and catechin contained in the teas beverages exhibits an anti-bacterial property. Therefore, in general, the SE is not required to be added to these teas beverages.
However, recently, in the production of the afore-mentioned teas beverages, there has been a tendency that the extraction of tea leaves is carried out at a low temperature to enhance taste of the teas beverages. In this case, the concentration of catechin extracted from tea leaves in the teas beverages becomes low, so that the growth of endospores in the teas beverages cannot be sufficiently prevented. On the contrary, if the teas beverages are heat-sterilized at an elevated temperature to prevent the spoilage thereof, taste or flavor of the teas beverages is disadvantageously lessened. In addition, especially in the case of the low-acidic beverages which are hot-filled in PET bottles or glass bottles after the heat sterilization, there arises such a problem that the beverages undergo secondary contamination from their containers or production lines.
Also, among the teas beverages, barley water or blended tea has no or extremely small catechin content and, therefore, easily suffers from the spoilage by the endospores. Further, even in the case of straight coffee, a certain kind of endospores can be grown and propagated therein, thereby still causing the spoilage thereof.
Also, in the case of foods which are subjected to retort-sterilization, such as boiled beans, Japanese hotchpotch, water-boiled vegetables, daily dish, Japanese chowder, pickles or seasoning materials, it is required that the sterilizing condition thereof is moderated in order to prevent the lowering of a quality thereof such as texture upon eating, or taste or flavor. However, in such a case, the thermoduric endospores still survives through the sterilization and, therefore, causes the spoilage of these foods. In order to solve the above problems, it is demanded that SE having an anti-bacterial property is added to clear soups or brothes of the afore-mentioned foods.